A STUDY OF 3-DIMENSIONAL NATURAL-CONVECTION IN HIGH-PRESSURE MERCURY LAMPS .2. WALL TEMPERATURE PROFILES AND INCLINATION ANGLES

A three-dimensional computational model has been adopted to investigate the natural convection transport of the high-pressure mercury arc discharge in a curved tube. The model solves the combined momentum, continuity, energy, electric field, and simplified radiation transfer equations. The present study investigates the degrees of uniformity of temperature distribution on the tube wall, and the impact of tube inclination angle with respect to gravity on the transport process and the resulting temperature distribution. Good agreements between the predictions and measurements have been obtained. It is found that the gross patterns of gas temperature distribution in mid-plane are rather insensitive to the inclination angle. The wall temperature distribution, however, exhibits substantially greater sensitivity to the inclination angle. This change of characteristics in wall temperature distribution has important effects on the performance of the arctube. © 1990.